The long term objective of the proposed research is to produce valid, sensitive, and economical instrumented tests of tremor, bradykinesia, and cogwheel rigidity for patients with Parkinson's Disease (1). The specific aims of the proposed research are 1) to validate simplified accelerometric measures of resting tremor, 2) to instrument and validate a variation of the Finger Oscillation Test (FOT) of bradykinesia, and 3) to further validate an accelerometric measure of cogwheel rigidity reported by Lance, Schwab, and Peterson (2), and Findley, Gresty, and Halmagyi (3). These three test use the same accelerometer and personal computer and therefore are more efficient and cost effective than using separate equipment for each test as is currently the norm (1). Validation will be economically accomplished by using 30 patients already enrolled in the funded study entitled DEPRENYL AND TOCOPHEROL ANTIOXIDATIVE THERAPY OF PARKINSONISM (DATATOP) (4,5) and 30 spouse/relative control subjects at Month 0, 1, 3, 6, 9, 12, 15, 18, 21, 24, and 25, or until levodopa therapy is begun, where upon their participation in the parent study is terminated after a one month washout period. Clinical status as reflected by the accelerometric measures of tremor, bradykinesia, and cogwheel rigidity will be correlated with the standard clinical assessments of these same symptoms. Positive results will provide valid, sensitive, and economical means of obtaining instrumented tests of tremor, bradykinesia, and rigidity in an outpatient setting.